Question

Tìm x
(x+1)²-4(x²-1)+(2x-2)²=0

Answer 1

(x + 1)² - 4(x - 1)² + (2x - 2)² = 0

x² + 2x + 1 - 4x² + 8x - 4 + 4x² - 8x + 4 = 0

x² + 2x + 1 = 0

(x + 1)² = 0

x + 1 = 0

x = -1

Answer 2

\(\left(x+1\right)^2-4\left(x^2-1\right)+\left(2x-2\right)^2=0\\\)

\(\Leftrightarrow x^2+2x+1-4x^2+4+4x^2-8x+4=0\)

\(\Leftrightarrow x^2-6x+9=0\)

$\Leftrightarrow$ \(\left(x-3\right)^2=0\)

$\Leftrightarrow$ $x=3$